The present invention refers to an apparatus for controlling peripheral devices through tongue movement, and to a method of processing or evaluating control signals for controlling peripheral devices through tongue movement.
It is generally known to assist disabled people, in particular quadriplegics with a control apparatus to operate peripheral devices such as computers, TV's, telephones and like devices by utilizing tongue movements. In this manner, handicapped people become capable to perform certain activities without assistance of others.
U.S. Pat. No. 4,728,812 discloses an oral machine controller for controlling operations of peripheral devices through tongue movement, and includes upper and lower dentition grips by which the upper and lower teeth in the jaw are locked in position. Through the tongue or tip of the tongue, a contact group or a potentiometer is actuated which is in communication with a processor, with the voltage potential being varied by linear movement of an actuator post along the length of the potentiometer. A drawback of this oral machine controller is its relatively large design which at operation is placed in front of the mouth. A further drawback is the required extreme shifting length to be covered by the actuator post in order to alter the voltage potential. For these reasons, this controller cannot be utilized to process rapidly following commands.
Swiss patent no. CH-PS 660,956 describes a control unit for handicapped persons by which a single contact carries out various control functions. Thus, commands must be sequentially processed via the single contact so that this control unit is also not suitable to process rapidly following instructions. Rather, the operator is required to proceed step-by-step to a desired menu in order to trigger the respective control function.
German patent publication DE-OS 1,943,824 discloses a control unit which is linked to a wheelchair and actuated by tongue movements to enable a quadriplegic to change the direction of motion. The tongue movement closes a respective current circuit between associated electrodes for motion of the wheelchair in a desired direction. Each direction of wheelchair motion is assigned a respective number of electrodes, resulting in an increased size of the overall control unit. Moreover, in order to actuate the electrode, the electrode plate must be moved to and from the operator, thus complicating the use of this control unit.
It is also known to place a tube in the mouth of a disabled person to transmit to a respective processor two instructions in form of aspirating or blowing through the pipe. Such aspiration and blowing technique has the same drawbacks with regard to a processing of rapidly incoming successive instructions as a processing of tongue-actuated electric contacts.
German patent no. DE 4,100,402 A1 discloses a mouth piece for disabled persons by which computers or other peripheral devices are controlled through use and processing of a tongue movement. The mouth piece resembles a joystick which is miniaturized so as to be usable during operation within the mouth of the operator. The mouth piece is actuated by the tongue which acts on a cage to close electrical contacts via a spring-loaded bar, with the closing of certain contacts in dependence on the tongue movement being quasi digital. Each case requires however a mechanical and electrical contact of the tongue-actuated pin with the pertaining contact leaves and center contact. During an extended use, the mouth piece is subjected to a corrosion of the contact surfaces so that a secure contacting cannot be ensured any more. Moreover, contact bounces may result in erroneous readings.